Rubber tube XL Slingbow Arms for the Adderini

cults3d

Shameless plug: I copied somewhat the idea for mounting Theratubes from this design:https://cults3d.com/en/3d-model/home/slingshot-arm-for-the-adderini-is-for-the-theratube-6mm The original design with short arms and using Theraband instead of tubes is a great idea and combines both a low profile as well as high draw weight. This comes with some disadvantages: - You have to serve your own bowstring (which was both interesting and time consuming for me) - Folded Theraband has a tendency to "break" where it is folded after intense shooting - Acceleration is quite "hard" and puts more stress to the bolts. Especially the cheaper ones have a tendency to break off at the end. My other "XL Slingbow arm" design aimed for mitigation of those issues. Using 8-10 cm Theratube Silver on each side gives you the opportunity to simple use 3-4 mm PP rope with a double knot on each end as string (similar to the Sliding Legolini). In terms of draw weight / shooting power I didn't see a big difference compared to the original Adderini arms plus 4 cm Theraband Gold. Acceleration is much softer for the bolts and at least during my rather short shooting series I didn't experience any failure of the cheaper China bolts with plastic "feathers". In regard to stress on the bolts my rating from low to high stress would be: - Adderini with XL-Arms / Sliding Legolini with Theratube - Adderini with 4 cm Theraband Gold and shorter original arms - Adderini with 6 cm Theraband Gold and shorter original arms - Mini Adder with 50 lbs steel bow Possibly the original Steambow Stinger bow adds a bit more stress to the bolts as the cheaper 50 lbs steel bow but I can not say for shure since I do not own one :-) With my other XL arm design I simply used the slingshot approach to attach the tube with slices of Theraband Gold wrapped around it several times. With the new design (holes for the rubber tube plus small "balls" to mount it) I aim for a re-usable attachment method. You can either use small steel balls with a diameter > 8 mm or simply print out the included "edgy balls". I've designed balls with diameters of 8 mm. This way you can try which ones fits best. If you finally still do not trust solely the ball, you can use a zip tie or some rope to close the end. This hole-ball method is often used for slingshots as well and is proven to provide a solid fit. Similar to my XL arms I can only stress again NOT to use too strong rubber tube (e.g. spear gun rubber). Use some common sense. I broke two XL arms being printed in PETG with 100% infill simply because I thought to myself "Hmmmmm....this could also work for Theraband Gold". You have be warned :-) For standard use (as described above) I guess PLA will we always sufficient if you use a decent wall thickness and somewhat reasonable infill (e.g. 1.6-2 mm / 30% infill). If unsure, use a more robust filament such as PETG. As for the Adderini: If you do not really need the smaller form factor, I would always go for the longer slingbow arms combined with PP rope as bow string. If you like to combine the benefits of Theratube with the orginal slim Adderini design, then use the other arms I linked above (which uses 6 mm rubber tubes instead).